Vigilantes on both sides of the divide in Ukraine have formed groups to protect buildings that they control. In this picture, antigovernment activists protect Kyiv's "Ukrainian House," which was seized by protesters on January 26.

As Ukraine's civil unrest spreads across Ukraine, with antigovernment protesters laying siege to official buildings in a dozen cities, jittery citizens are taking security into their own hands.

Self-defense groups are hastily being formed in the Russian-speaking east, President Viktor Yanukovych's traditional power base, to bar protesters from seizing control of local administrations.

In the European-leaning, western part of Ukraine, local residents supporting Kyiv's Euromaidan protests are also conducting patrols and guarding government buildings seized by demonstrators last week.

But there are fears that the mushrooming of rival vigilante groups, instead of bringing order back to the streets, will only fuel violence and divisions.

"There are risks that they will clash," says Kyiv-based political analyst Taras Berezovets. "It is an extremely dangerous, uncontrollable scenario."

Yanukovych sympathizers, including Cossacks and Afghanistan war veterans, have already lent police a hand in breaking up pro-EU rallies and repelling protesters seeking to take over government buildings in Zaporizhzhya, Dnipropetrovsk, Cherkasy, Sumy, and Odesa.

Emboldened by their success, they are now getting organized into special task forces to keep what they describe as violent, radical antigovernment rioters at bay.

Ready To Fight

National Unity is one of several groups currently rallying volunteers in the southern city of Odesa.

Known for its anti-EU stance, the youth organization says more than 1,000 people have already come forward over the past four days.

According to its leader, 28-year-old Anton Davydchenko, the new units will be ready to take up arms against protesters if needed.

"We call on everyone to stay calm and we hope that these units will not have to be involved in conflict situations," he says. "But in our country, it's better to be prepared for any turn of events. We will never give them our cheek to be slapped. If they come to us with weapons, we will meet them with weapons."

With police outnumbered and facing fierce resistance from a hard core of radical protesters in Kyiv, authorities have backed the initiative,

Some opposition activists believe the newly-formed groups are a cover for government efforts to boost the number of "titushky," thugs believed to be hired by authorities to assault protesters and stage provocations.

Donetsk and Luhansk, two eastern industrial cities that rely heavily on Russia for its trade, have formally authorized vigilante groups and Yanukovych's cabinet has reportedly tasked the justice ministry with legalizing such groups nationwide.

Pro-European Ukrainians, too, are taking steps to defend themselves.

Civilian patrols are already in place in several cities, including the western city of Lviv.

"Soon we will be able to talk about forming a serious organization capable of defending democracy, the fatherland, and the constitution," he says. "The situation is dangerous in Ukraine. There are fears that the regime will strike and that Lviv will see events similar to what is now taking place in Kyiv."

In Kyiv, Euromaidan organizers have ramped up security on Independence Square.

They are also encouraging residents to attend self-defense classes that are being held on the square by former military officers.

RFE/RL correspondent Halina Tereshchuk contributed to this report from Lviv